Identification of 2,3-disubstituted pyridines as potent,orally active PDE4 inhibitors

A series of 2,3-disubstituted pyridines were synthesized and evaluated for their PDE4 inhibitory activity. We successfully modified undesirable cyano group of initial lead compound 2 to 4-pyridyl group with improvement of in vitro efficacy and optimized the position of nitrogen atoms in pyridine moiety and alkylene linker. The most potent compound showed significant efficacy in animal models of asthma and inflammation.     

Synthesis and evaluation of tripeptidic plasmin inhibitors with nitrile as warhead

Plasmin is best known as the key molecule in the fibrinolytic system, which is critical for clot lysis and can initiate matrix metalloproteinase (MMP) activation cascade. Along with MMP, plasmin is suggested to be involved in physiological processes that are linked to the risk of carcinoma formation. Plasmin inhibitors could be perceived as a promising new principle in the treatment of diseases triggered by plasmin. On the basis of the peptidic sequence derived from the synthetic plasmin substrate, a series of peptidic plasmin inhibitors possessing nitrile as warhead were prepared and evaluated for their inhibitory activities against plasmin and other serine proteases, plasma kallikrein and urokinase. The most potent peptidic inhibitors with the nitrile warhead exhibit the potency toward plasmin (IC₅₀ = 7.7–11 μM) and are characterized by their selectivity profile against plasma kallikrein and urokinase. The results and molecular modeling of the peptidic inhibitor complexed with plasmin reveal that the P2 residue makes favorable contacts with the open binding pocket comprising the S2 and S3 subsites of plasmin. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.     

Iodine-mediated oxidative cyclization for one pot synthesis of new 8-hydroxyquinaldine derivatives containing a N-phenylpyrazole moiety as pesticidal agents

In continuation of our research aimed at discovery and development of new pesticidal agents, a series of new 8-hydroxyquinaldine derivatives containing a N–phenylpyrazole moiety were prepared and their structures were characterized by ¹H NMR, IR, ESI-MS and mp. Meanwhile, an efficient way of using iodine-mediated oxidative cyclization for one pot synthesis of these 8-hydroxyquinaldine derivatives containing a N–phenylpyrazole moiety was developed. The bioassay showed that compounds 8g and 9f exhibited potent pesticidal activities against both Mythimna separata Walker and Plutella xylostella Linnaeus. The structure–activity relationships were also discussed.     

Carbamazepine derivatives with P2X4 receptor-blocking activity

Antagonists for the P2 receptor subtype P2X4, an ATP-activated cation channel receptor, have potential as novel drugs for the treatment of neuropathic pain and other inflammatory diseases. In the present study, a series of 47 carbamazepine derivatives including 32 novel compounds were designed, synthesized, and evaluated as P2X4 receptor antagonists. Their potency to inhibit ATP-induced calcium influx in 1321N1 astrocytoma cells stably transfected with the human P2X4 receptor was determined. Additionally, species selectivity (human, rat, mouse) and receptor subtype selectivity (P2X4 vs P2X1, 2, 3, 7) were investigated for selected derivatives. The most potent compound of the present series, which exhibited an allosteric mechanism of P2X4 inhibition, was N,N-diisopropyl-5H-dibenz[b,f]azepine-5-carboxamide (34, IC₅₀ of 3.44 μM). The present study extends the so far very limited knowledge on structure–activity relationships of P2X4 receptor antagonists.     

Identification of 2,3-disubstituted pyridines as potent,non-emetic PDE4 inhibitors

A series of 2,3-disubstituted pyridines were synthesized as potential non-emetic PDE4 inhibitors. To decrease brain exposure and minimize emesis, we modified the lipophilic moiety of a series of emetic PDE4 inhibitors and found that introduction of a hydroxy group into the pyridine moiety of the side chain led to non-emetic compounds with preserved PDE4 inhibitory activity. Following optimization at the phenoxy group, we identified compound 1 as a potent non-emetic PDE4 inhibitor. Compound 1 showed significant efficacy in an animal model of asthma without inducing emesis.     

Design,synthesis, and anticancer activity of C8-substituted-4′-thionucleosides as potential HSP90 inhibitors

A series of C8-substituted-4′-thioadenosine analogs 3a–3g, 15, and 17 and their truncated derivatives 4a–4j, 23–25, and 27 have been successfully synthesized from d-ribose and d-mannose, respectively, employing Pummerer type or Vorbrüggen condensation reactions and the functionalization at the C8-position of nucleobase via Stille coupling or nucleophilic aromatic substitution reactions as key steps. All the synthesized compounds were assayed for their HSP90 inhibitory activity, but they were found to be inactive up to 100 μM. However, the 8-iodo derivatives 15, 17, and 27 exhibited potent anticancer activity, indicating that different mechanism of action might be involved in their biological activity.     

Carbonic anhydrase inhibitors: Synthesis and inhibition of the cytosolic mammalian carbonic anhydrase isoforms I,II and VII with benzene sulfonamides incorporating 4,5,6,7-tetrachlorophthalimide moiety

A series of 4,5,6,7-tetrachloro-1,3-dioxoisoindolin-2-yl benzenesulfonamide derivatives (compounds 1–8) was synthesized by reaction of benzene sulfonamides incorporating primary amino moieties with 4,5,6,7-tetrachlorophthalic anhydride. These sulfonamides were assayed as inhibitors of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1). Some of these compounds showed very good in vitro human carbonic anhydrase (hCA) isoforms I, II and VII inhibitory properties, with affinities in the low nanomolar range. Inhibition activities against hCA I were in the range of 159–444 nM; against hCA II in the range of 2.4–4515 nM, and against hCA VII in the range of 1.3–469 nM. The structure–activity relationship (SAR) with this series of sulfonamides is straightforward, with the main features leading to good activity for each isoform being established.     

Optimization and biological evaluation of celastrol derivatives as Hsp90–Cdc37 interaction disruptors with improved druglike properties

Heat shock protein 90 (Hsp90) as a molecular target for oncology therapeutics has attracted much attention in the last decade. The Hsp90 multichaperone complex has important roles in the growth and/or survival of cancer cells. Cdc37, as a cochaperone, associates kinase clients to Hsp90 and promotes the development of malignant tumors. Disrupting the Hsp90–Cdc37 interaction provides an alternative strategy to inhibit the function of Hsp90 for cancer therapy. Celastrol, as a natural product, can disrupt the Hsp90–Cdc37 interaction and induce degradation of kinase clients. The study conducted here attempted to elucidate the structure–activity relationship of celastrol derivatives as Hsp90–Cdc37 disruptors and to improve the druglike properties. 23 celastrol derivatives were designed, synthesized, and the biological activities and physicochemical properties were determined. The derivative CEL20 showed improved Hsp90–Cdc37 disruption activity, anti-proliferative activities as well as druglike properties. Additionally, CEL20 induced clients degradation, cell cycle arrest and apoptosis in Panc-1 cells. This study can provide reference for the discovery of novel Hsp90–Cdc37 disruptors.     

Synthesis,biological evaluation,and molecular docking studies of novel 2-styryl-5-nitroimidazole derivatives containing 1,4-benzodioxan moiety as FAK inhibitors with anticancer activity

A series of 2-styryl-5-nitroimidazole derivatives containing 1,4-benzodioxan moiety (3a–3r) has been designed, synthesized and their biological activities were also evaluated as potential antiproliferation and focal adhesion kinase (FAK) inhibitors. Among all the compounds, 3p showed the most potent activity in vitro which inhibited the growth of A549 with IC₅₀ value of 3.11 μM and Hela with IC₅₀ value of 2.54 μM respectively. Compound 3p also exhibited significant FAK inhibitory activity (IC₅₀ = 0.45 μM). Docking simulation was performed for compound 3p into the FAK structure active site to determine the probable binding model.     

Carbonic anhydrase inhibitors: Synthesis and inhibition of the human carbonic anhydrase isoforms I,II, VII,IX and XII with benzene sulfonamides incorporating 4,5,6,7-tetrabromophthalimide moiety

A series of 4,5,6,7-tetrabromo-1,3-dioxoisoindolin-2-yl benzenesulfonamide derivatives (compounds 1–8) was synthesized by reaction of benzene sulfonamide derivatives with 4,5,6,7-tetrabromophthalic anhydride moiety. These new sulfonamides were investigated as inhibitors of the zinc metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) and more specifically against the human (h) cytosolic isoforms hCA I, II and VII and the transmembrane tumor-associated isoform hCA IX and XII. The new compounds were good hCA I inhibitors (Kis in the range of 143 to >10,000 nM), but were moderately effective, as hCA II inhibitors (Kis of 47–190 nM) and poor hCA VII inhibitors (Kis in the range of 54–175 nM) compared to acetazolamide. The tumor-associated hCA IX was effectively inhibited with Kis ranging between 8.5 and 234 nM and hCA XII with inhibition constants in the range of 6.1–197 nM with high selectivity ratio. The structure–activity relationship (SAR) with this series of sulfonamides is straightforward, with the main features leading to good activity for each isoforms being established. The high sequence hCA alignment homology and molecular docking study of compounds was performed to rationalize the SAR reported over here.     

Structure–activity relationship of mastoparan analogs: Effects of the number and positioning of Lys residues on secondary structure,interaction with membrane-mimetic systems and biological activity

In this study, a series of mastoparan analogs were engineered based on the strategies of Ala and Lys scanning in relation to the sequences of classical mastoparans. Ten analog mastoparans, presenting from zero to six Lys residues in their sequences were synthesized and assayed for some typical biological activities for this group of peptide: mast cell degranulation, hemolysis, and antibiosis. In relation to mast cell degranulation, the apparent structural requirement to optimize this activity was the existence of one or two Lys residues at positions 8 and/or 9. In relation to hemolysis, one structural feature that strongly correlated with the potency of this activity was the number of amino acid residues from the C-terminus of each peptide continuously embedded into the zwitterionic membrane of erythrocytes-mimicking liposomes, probably due to the contribution of this structural feature to the membrane perturbation. The antibiotic activity of mastoparan analogs was directly dependent on the apparent extension of their hydrophilic surface, i.e., their molecules must have from four to six Lys residues between positions 4 and 11 of the peptide chain to achieve activities comparable to or higher than the reference antibiotic compounds. The optimization of the antibacterial activity of the mastoparans must consider Lys residues at the positions 4, 5, 7, 8, 9, and 11 of the tetradecapeptide chain, with the other positions occupied by hydrophobic residues, and with the C-terminal residue in the amidated form. These requirements resulted in highly active AMPs with greatly reduced (or no) hemolytic and mast cell degranulating activities.     

Modification of agonist binding moiety in hybrid derivative 5/7-{[2-(4-aryl-piperazin-1-yl)-ethyl]-propyl-amino}-5,6,7,8-tetrahydro-naphthalen-1-ol/-2-amino versions: Impact on functional activity and selectivity for dopamine D2/D3 receptors

The goal of the present study was to explore, in our previously developed hybrid template, the effect of introduction of additional heterocyclic rings (mimicking catechol hydroxyl groups as bioisosteric replacement) on selectivity and affinity for the D₃ versus D₂ receptor. In addition, we wanted to explore the effect of derivatization of functional groups of the agonist binding moiety in compounds developed by us earlier from the hybrid template. Binding affinity (K_i) of the new compounds was measured with tritiated spiperone as the radioligand and HEK-293 cells expressing either D₂ or D₃ receptors. Functional activity of selected compounds was assessed in the GTPγS binding assay. In the imidazole series, compound 10a exhibited the highest D₃ affinity whereas the indole derivative 13 exhibited similar high D₃ affinity. Functionalization of the amino group in agonist (+)-9d with different sulfonamides derivatives improved the D₃ affinity significantly with (+)-14f exhibiting the highest affinity. However, functionalization of the hydroxyl and amino groups of 15 and (+)-9d, known agonist and partial agonist, to sulfonate ester and amide in general modulated the affinity. In both cases loss of agonist potency resulted from such derivatization.     

Identification and characterization of P15RS, a novel P15(INK4b) related gene on G1/S progression

To screen genes involved in P15(INK4b) regulation during cell cycle, differential display method was applied to compare mRNAs from G(1) synchronized cells of MLIK6, which overexpressed P15(INK4b) gene, and its control MLC2. By using this approach, 15 cDNA fragments that were preferentially expressed in MLIK6 cells, but not in MLC2 cells, were screened out. A novel gene named P15RS was identified with further analysis. Combining the sequence from DD-PCR, homology analysis against EST database and RACE, a 4,404 bp complete cDNA sequence of P15RS was generated. Sequence analysis revealed that P15RS cDNA encoded a 312-amino-acid peptide containing a RAR domain that is involved in regulation of nuclear pre-mRNA, which suggests that P15RS may be a nuclear regulation protein. Genomic sequence analysis demonstrated that human P15RS gene was localized on chromosome 18q12 with seven exons and six introns. Expressing antisense P15RS in MLIK6 cells can up-regulate the expression of cyclinD1 and cyclinE. These data indicate that P15RS may act as a negative regulator in G(1) phase.     

Design and synthesis of 6,7-methylenedioxy-4-substituted phenylquinolin-2(1H)-one derivatives as novel anticancer agents that induce apoptosis with cell cycle arrest at G2/M phase

Novel 6,7-methylenedioxy-4-substituted phenylquinolin-2(1H)-one derivatives 12a–n were designed and prepared through an intramolecular cyclization reaction and evaluated for in vitro anticancer activity. Among the synthesized compounds, 6,7-methylenedioxy-4-(2,4-dimethoxyphenyl)quinolin-2(1H)-one (12e) displayed potent cytotoxicity against several different tumor cell lines at a sub-micromolar level. Furthermore, results of fluorescence-activated cell sorting (FACS) analysis suggested that 12e induced cell cycle arrest in the G2/M phase accompanied by apoptosis in HL-60 and H460 cells. This action was confirmed by Hoechst staining and caspase-3 activation. Due to their easy synthesis and remarkable biological activities, 4-phenylquinolin-2(1H)-one analogs (4-PQs) are promising new anticancer leads based on the quinoline scaffold. Accordingly, compound 12e was identified as a new lead compound that merits further optimization and development as an anticancer candidate.     

Coronaridine congeners inhibit human α3β4 nicotinic acetylcholine receptors by interacting with luminal and non-luminal sites

To characterize the interaction of coronaridine congeners with human (h) α3β4 nicotinic acetylcholine receptors (AChRs), structural and functional approaches were used. The Ca²⁺ influx results established that coronaridine congeners noncompetitively inhibit hα3β4 AChRs with the following potency (IC₅₀'s in μM) sequence: (−)-ibogamine (0.62 ± 0.23) ∼ (+)-catharanthine (0.68 ± 0.10) > (−)-ibogaine (0.95 ± 0.10) > (±)-18-methoxycoronaridine [(±)-18-MC] (1.47 ± 0.21) > (−)-voacangine (2.28 ± 0.33) > (±)-18-methylaminocoronaridine (2.62 ± 0.57 μM) ∼ (±)-18-hydroxycoronaridine (2.81 ± 0.54) > (−)-noribogaine (6.82 ± 0.78). A good linear correlation (r² = 0.771) between the calculated IC₅₀ values and their polar surface area was found, suggesting that this is an important structural feature for its activity. The radioligand competition results indicate that (±)-18-MC and (−)-ibogaine partially inhibit [³H]imipramine binding by an allosteric mechanism. Molecular docking, molecular dynamics, and in silico mutation results suggest that protonated (−)-18-MC binds to luminal [i.e., β4-Phe255 (phenylalanine/valine ring; position 13′), and α3-Leu250 and β4-Leu251 (leucine ring; position 9′)], non-luminal, and intersubunit sites. The pharmacophore model suggests that nitrogens from the ibogamine core as well as methylamino, hydroxyl, and methoxyl moieties at position 18 form hydrogen bonds. Collectively our data indicate that coronaridine congeners inhibit hα3β4 AChRs by blocking the ion channel's lumen and probably by additional negative allosteric mechanisms by interacting with a series of non-luminal sites.     

Studies on structure activity relationship of some dihydroxy-4-methylcoumarin antioxidants based on their interaction with Fe(III) and ADP

Three dihydroxy-4-methylcoumarin (DHMC) derivatives, namely 7,8-DHMC, 6,7-DHMC and 5,7-DHMC alone and complexed with Fe (III) and ADP have been tested for their antioxidative potential. Chemical speciation studies and formation constants reveal the formation of strong DHMC–Fe–ADP (1:1:1) ternary complex. In vitro studies were done for their antioxidative property by scavenging the superoxide radicals (O ₂ ^– ) generated by xanthine + xanthine oxidase (XO) reaction. The IC₅₀ values for 7,8-DHMC, 6,7-DHMC and 5,7-DHMC and their ternary complexes with Fe (III)–ADP worked out to be 34.0 M, 62.0 M, 8.80 mM and 10.5, 11.5 and 148.5 M, respectively. The results indicate that O ₂ ^– scavenging potential of all the three DHMCs increased significantly after forming the ternary complex with Fe(III) and ADP. The structure activity relationship studies suggest that the introduction of hydroxyl group at 7th and 8th positions in the coumarins, irrespective of Fe(III)–ADP complexation, increases the antioxidative efficacy. No change in uric acid production in the reactions done for all studies further reveals that the coumarin derivatives and their complexes were the only causative factors for O ₂ ^– scavenging and not the suppression of the enzyme, xanthine oxidase.Published online: March 2005     

血清S1P、SFRP1、TIM4、SFRP5与成人支气管哮喘急性发作期患者肺功能、气道炎症和治疗后再次急性复发的关系

摘要 目的：观察血清分泌型卷曲相关蛋白1（SFRP1）、分泌型卷曲相关蛋白5（SFRP5）、1-磷酸鞘氨醇（S1P）、T细胞免疫球蛋白域及黏蛋白域蛋白4（TIM4）与成人支气管哮喘急性发作期患者肺功能、气道炎症和治疗后再次急性复发的关系。方法：选择火箭军特色医学中心2016年7月~2020年8月期间收治的120例成人支气管哮喘患者,其中47例缓解期患者纳为缓解组,73例急性发作期患者纳为发作组。对比发作组、缓解组血清S1P、SFRP1、TIM4、SFRP5水平、肺功能[第1秒用力呼气容积（FEV₁）、用力肺活量（FVC）、FEV₁/FVC]、气道炎症[血清总免疫球蛋白E（IgE）、痰嗜酸粒细胞、呼出气一氧化氮（FeNO）、血嗜酸粒细胞],治疗结束后以门诊复查或电话的形式进行随访1年,根据1年内是否再次急性复发分组,分为复发组和未复发组,对比复发组和未复发组的血清S1P、SFRP1、TIM4、SFRP5水平。结果：发作组的S1P、SFRP1、TIM4高于缓解组,SFRP5低于缓解组（P<0.05）。发作组的FEV₁、FVC、FEV₁/FVC低于缓解组（P<0.05）。发作组的血清总IgE、嗜酸粒细胞、FeNO、血嗜酸粒细胞高于缓解组（P<0.05）。Pearson相关性分析结果显示,S1P、SFRP1、TIM4与FEV₁、FVC、FEV₁/FVC呈负相关（P<0.05）,而与血清总IgE、嗜酸粒细胞、FeNO、血嗜酸粒细胞均呈正相关（P<0.05）。SFRP5与FEV₁、FVC、FEV₁/FVC呈正相关（P<0.05）,而与血清总IgE、嗜酸粒细胞、FeNO、血嗜酸粒细胞均呈负相关（P<0.05）。复发组的S1P、SFRP1、TIM4高于未复发组,SFRP5低于未复发组（P<0.05）。结论：成人支气管哮喘急性发作期患者S1P、SFRP1、TIM4水平异常升高,SFRP5异常降低,且与肺功能、气道炎症、再次急性复发均有一定关系。